title: Effect of dietary potassium and anionic salts on acid-base and mineral status in periparturient cows.
abstract: Dry cow diets based on grassland forage from intensive production contain high amounts of K and could be responsible for a reduced ability to maintain Ca homoeostasis. The aim of this study was to determine whether a moderate anionic salt supplementation to a forage-based pre-calving diet with varying native K content affects the mineral and acid-base status in transition cows. Twenty-four dry and pregnant Holstein cows, without antecedent episodes of clinical hypocalcemia, were assigned to two diets during the last 4 weeks before estimated calving date. Twelve cows were fed a hay-based diet low in K (18 g K/kg DM), and 12, a hay-based diet high in K (35 g K/kg DM). Within each diet, six cows received anionic salts during the last 2 weeks before the estimated calving day. After calving, all cows received the high K diet ad libitum. Blood samples were taken daily from day 11 pre-partum to day 5 post-partum. Urine samples were taken on days 7 and 2 pre-partum and on day 2 post-partum. The anionic salt did not alter feed intake during the pre-partum period. Serum Ca was not influenced by the dietary treatments. Feeding pre-partum diets with low K concentrations induced a reduced metabolic alkalotic charge, as indicated by reduced pre-partum urinary base-acid quotient. Transition cows fed the low K diet including anionic salts induced a mild metabolic acidosis before calving, as indicated by higher urinary Ca, lower urinary pH and net acid-base excretion. Although serum Ca during the post-partum period was not affected by dietary treatment, feeding a low K diet moderately supplemented with anionic salts to reach a dietary cation-anion difference close to zero permitted to obtain a metabolic response in periparturient cows without altering the dry matter intake.
authors.affiliation: Agroscope, Institute for Livestock Sciences, Posieux, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Rérat
authors.forename: P
authors.initials: P
authors.lastname: Schlegel
mesh_terms: D000136:Acid-Base Equilibrium / Q000187:drug effects*; D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D000838:Anions / Q000032:analysis / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D002417:Cattle / Q000502:physiology*; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements; D005260:Female; D006706:Homeostasis; D036801:Parturition; D058725:Peripartum Period / Q000502:physiology*; D017419:Potassium, Dietary / Q000494:pharmacology*; D011247:Pregnancy; D013997:Time Factors
chemical_list: D000838:Anions; D017419:Potassium, Dietary; D002118:Calcium
keywords: acid-base status; dairy cow; dietary cation-anion difference; potassium